The cities of San Francisco and New Orleans on Aug. 12 ordered patrons to show proof of Covid-19 vaccinations to enter restaurants, gyms and other venues, joining New York in a severe step designed to contain the fast-spreading Delta variant.

New York City will become the first major U.S. city to require proof of Covid-19 vaccination for customers and staff at restaurants, gyms and other indoor businesses as the country enters a new phase of battling the highly contagious Delta variant.